Method of producing cymene



Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE,

mvnt w. HUMIPHREY, or "wmron, NEW JEEsEY, ASSIGNOR T0 HERCULES POWDER. COMPANY, or wnmmo'ron, DELAWARE, A CORPORATION or DELAWARE MECPHOD OF PRODUCING GYMENE No Drawing.

in the presence of a catalyst. As a result of i the treatmentpolymerization products, sat- V urated hydrocarbons and cymene C H are produced. The cymene may be readily separated from the polymerization products by fractionation and it may also be separated by chemical treatment from saturated hydro:

carbons, as para-menthane, C H which may be formed.

In accordance with my invention, I may utilize as a catalyst, for example, 'fullers earth, kieselguhr, and the like. The dipentene, or other terpenes, may be treated in either the liquid or vapor phase.

In accordance with my invention the paracymene, formed by the treatment of the dipentene, or other terpenes, may be readily separated by fractionation from thehigher boiling polymerization products formed by the treatment; and while the crudecymene on separation from the polymerization-prod ucts may be generally used in place of pure cymene, for example, for certain solvent purposes, separation of the cymene from other products, as para-menthane and possibly small amounts of other saturatedhydrocarbons formed by the treatment may be efiected, for example, in the form of the barium salt of its sulfonic acid by sulfonation of the cymene with sulfuric acid by known methods, the menthane being unattacked, or separation may be effected by nitration of the crude cymene with mixed acid, since the cymene nitrates more readily than does the para-menthane.

In the carrying out of the process according' to my invention, say 305 parts of terpenes, b. p. 170 C.185 C. are heated under a reflux condenser with 75 parts of fullers earth at a temperature within about the range 170 C. 200 C. for a period of ten hours. After the treatment is completed,

Application men m 26,

1928. Serial No. 295,615.

about 125 parts of crude cymene is obtained by fractionationitrom a residual oil consisting chiefly of polymerized terpenes.

The crude product obtained according to the procedure outlined above will contain para-cymene, para-menthane and also a large proportion of polymerized terpenes. If desired the process may be'carried out at a higher temperature, say within the range 190 C.250 C. under'increased pressure, say a pressure withinv about the range 40130 pounds per square inch, with, however, the production of cymene and saturated hydrocarbons in proportions differing from those obtained at lower temperatures.

In the carrying out of the method in accordance with my invention, the'heating of, for example, dipentene in the presence of a catalyst, as fullers earth, about two-thirds of the dipentene is converted into high boiling polymers (C H distilling above 300 C. while the remainder of thedipentene, at the same time, undergoes simultaneous hydrogenation and dehydrogenation with the formation of para-cymene and para-menthane. The reaction resulting in the formation of para-cymene and para-menthane may be represented thus:

'of about 190? C.-200 C. under a pressure of about 40-50 pounds. The treatment in addition to higher polymers will yield about, 160 parts of non olymerized oil distilling below about 250 and which on fraction- The operation may also be conducted at.

higher temperatures e. g. about240 C.250 C. for 6 hours under 110-130 pounds gauge pressure, yielding a crude product which has as r. of .885 with '50 distillin between.

P g g 'uc't and collecting the fraction oiling beabout 160 C. and 195 C.

The crude product produced in accordance with my process will,- as has been indicated,

polymerized terp'enes and more speci cally the product may contain about aracymene, 15% para-menthane and (@%polymerized terpenes. The crude product will, on fractionation, yield a largely within the range 1 O.-185 (1., having a specific gravity of about 0.846 at 15'.6 C. and comprising chiefly para-cymene and para-menthane.-

I may be utilized in c ene will nitrate more The method in accordance with my invention may be carried out with the dipentene, or other terpenes, in liquid or vapor please. The conversion in vapor phase may effected, for example, by passing vapors of the dipentene, or other terpenes, over fullers earth heated to a temperature within about the range 200 C.300 C.

The crude product, as originally produced,

but if it is desire to se arate the cymene; such may be accomplished i crude product, i. e. that portion boiling between about 170 (Land 185 C. with sul phuric acid for the production of thesulfonic acid of the cymene, which is easily separated.

from theunattacked menthane. For exam-v le, se aration of the cymene may be efl'ected y sul onation of say 100 parts of the crude product with 200 parts of sulfuric acid and.

subsequent separation of the barium salt. If

the crude cymene with mixed acid, since the t e para-menthane. a

According to my invention cymene 18 produced in 'a relatively simple and inexpensive manner, the product as produced being neucapablerof being rdadilg menthane and cymene erivatives;

It will be understood tlratwhere mum claims appended hereto I- specify fullers earth, I intend toinclude 'kieselguhr and other silicious and argillaceous earths as equivalents.

.Havi now ters Patent is:v 1. The method of producing cymene which includes subjectinga terpene heat in the -"tial comprise para-cymene, para-menthamii and a product boiling y treatment of the readily than will fully described my'invention, what I c aim and desire toprotect by Let presence of fullers earth to effect the conversion of a part thereof into cymene.

2. The method of roducing cymene which includes subjecting ipentene to heat in the presence of fullers earth to effect the conversion of a part thereof into cymene. J

3. Thc method of producingcymene which includes subjecting dipentene to heat in the presence offullers earth to effect partial conversioriinto cymene, fractionatin the prod-- ,Iow about 200 C. and consisting in substanart' of para-cymene.

4. includes subjecting ipentene to heat in the" presence offullersearth to effect partlal conversion into cymene, fractionating the roduct, collecting the fraction boiling beow about 195? C. and consisting in substantial part of para-cymene andsubJectmgthe fraction to sulfonation for the 'se'paratiomof para-cymene.

In testimony I hereunto set In hand at Kenvil, N. J on this 23rd day of uly, 1928.. v. 4

IRVIN W. HUMPHREY. a

he method of roducing cymenewhich I ofjwhich invention, I have L general in place of cymene, 

